nanosleep

Synopsis

Description

The nanosleep() function causes the current thread to be suspended from
execution until either the time interval specified by the rqtp argument has
elapsed or a signal is delivered to the calling thread and its
action is to invoke a signal-catching function or to terminate the process. The
suspension time may be longer than requested because the argument value is
rounded up to an integer multiple of the sleep resolution or because
of the scheduling of other activity by the system. But, except for
the case of being interrupted by a signal, the suspension time will not
be less than the time specified by rqtp, as measured by the
system clock, CLOCK_REALTIME.

The use of the nanosleep() function has no effect on the action
or blockage of any signal.

Return Values

If the nanosleep() function returns because the requested time has elapsed, its
return value is 0.

If the nanosleep() function returns because it has been interrupted by a
signal, the function returns a value of -1 and sets errno to
indicate the interruption. If the rmtp argument is non-NULL, the timespec structure referenced
by it is updated to contain the amount of time remaining in
the interval (the requested time minus the time actually slept). If the
rmtp argument is NULL, the remaining time is not returned.

If nanosleep() fails, it returns -1 and sets errno to indicate the
error.

Errors

The nanosleep() function will fail if:

EINTR

The nanosleep() function was interrupted by a signal.

EINVAL

The rqtp argument specified a nanosecond value less than zero or greater than or equal to 1000 million.